Many engines may exhibit poor performance when first started at cold ambient conditions until a desired operating temperature is reached. A typical measure to improve a performance of an engine, especially a diesel engine, during cold start conditions may be to advance ignition timing thus raising firing pressures of the engine. However, these high firing pressures may strain various engine components, including head gaskets and power generation components, such as pistons, connecting rods, crankshafts, intake, and/or exhaust valves. Moreover, a typical vehicle operator must sometimes wait for the engine to warm up before heat is available in the vehicle cab.
Other measures that have been taken in the past to improve quality of operation for engines that are starting in cold conditions have included raising the exhaust back pressure to make the engine work harder during warm-up and the addition of engine components, for example, fuel-fired or electrical heaters or secondary heater units for a vehicle cab. Such measures may be partly effective in accomplishing a faster warm-up for an engine or cab, but are usually very costly and complicated in their implementation.
Accordingly, there is a need for an engine heating system that accomplishes a short engine warm-up period and that is simple and cost effective in its implementation.
An apparatus and method are disclosed to aid in engine warm-up following engine startup at cold conditions. An apparatus is disclosed that includes an exhaust gas recirculation (EGR) cooler fluidly communicating with an intake system and an exhaust system of an engine. An EGR valve is in fluid communication with the exhaust side of the EGR cooler. A turbocharger turbine has an inlet disposed in fluid communication with the exhaust system and an outlet in fluid communication with a vehicle exhaust system. A bypass valve is in fluid communication with the exhaust side of the EGR cooler and the outlet of the turbine. A cooling system may be partially integrated with the internal combustion engine, and include a heater supply passage and a heater return passage. A cabin heater is in fluid communication with the cooling system, wherein a flow path of coolant is defined between the coolant side of the EGR cooler, the heater supply passage, the heater, the heater return passage, and the engine.
A method is disclosed for reducing a time required to warm-up an engine includes the step of determining whether cold conditions exist when the engine is first started. At times when the engine is first started under cold conditions, an operational state of the engine is determined. When the engine is in an idling mode, a bypass valve is opened that allows exhaust gas to pass through an exhaust gas recirculation (EGR) cooler but not the intake system of the engine so as to heat a flow of coolant passing through the EGR cooler. The flow of coolant from the EGR cooler is routed to a cabin heater of a vehicle.
A method of operating a turbocharged internal combustion engine is disclosed that includes the step of determining that the engine requires warming by comparing an engine operating parameter to a predetermined value. A flow of exhaust gas may be rerouted around a turbocharger turbine and through a first heat exchanger. The first heat exchanger may be used to warm a flow of coolant passing therethrough. The flow of coolant from the first heat exchanger may then be routed into a second heat exchanger disposed in a cabin of a vehicle.